I'm really struggling with ornstein and smough I need tips

I started playing souls game this year starting with Bloodborne I did that and moved onto dark souls and up to this point the bosses haven't been too challenging but these guys!!!! these two guysss I've died so many times

I've managed to get to the second phase a few times always killing Smough first as I want Ornsteins armor but I keep getting my ass kicked in the first phase that by the time I'm at the second phase I have less than half of my heals left

I would appreciate tips to make the first phase easier and tips for Ornsteins second phase